Topband: Vertical SWR Problems

George & Marijke Guerin gmguerin at voyager.net
Thu Dec 2 11:17:26 EST 2004


Hi All,

Let me address two issues.
Ground effectiveness:
To my ears the team vertical guys were not loud from 3D2XA.  I believe Ken's 
note about only 2 radials is the issue.  One needs to have a minimum of 30 
radials each about 20 meters/66 feet or longer as a minimum unless one is on 
a saltwater flat.
Some years ago a crew with a Battle Creek Special in central Oceana area 
only put out a few radials the first week and had a very poor signal.  When 
they put out the rest of the radials they put out a decent signal and worked 
the entire North American continent and some Europe on their sunrise.
For what it is worth, 32 radials 1/8 wavelength long is better than 16 
radials 1/4 wavelength long, as the larger number of radials handles the 
near in return currents much better

Base loaded verticals:
As to base loading Titanex verticals, yes the antenna may have a 11 or 12 
ohm feed point impedance, with a lot of capacitive reactance, but they 
supply and/or recommend a large inductor to base load the vertical up to 160 
meters.  Tapping the loading coil up some number of turns from the 
bottom/ground end will find a match close to 50 ohms for the coax cable feed 
line.

73    George    K8GG




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